Very small acceptance filter (setting variables for batch) including opening angle.

class PHadesAcc : public PBulkInterface {

private:
    Double_t *hadacc, *opang;

 public:
    
    PHadesAcc();

    Bool_t Modify(PParticle ** stack, int *decay_done, int *num, int stacksize);  //bulk interface

    ClassDef(PHadesAcc, 0) 
};

PHadesAcc::PHadesAcc() {
    hadacc = makeStaticData()->GetBatchValue("_hadacc");
    opang  = makeStaticData()->GetBatchValue("_opang");
};

bool PHadesAcc::Modify(PParticle **stack, int *decay_done, int *num, int stacksize) {

    *hadacc = 1.;

    for (int i=0; i<*num; i++) {
	PParticle *cur = stack[i];
//	cur->Print();

	if (cur->Is("pi+") || cur->Is("pi-")|| cur->Is("p") 
	    || cur->LeptonN()) {

#if 0
	    double momentum_resolution = 0.05;
	    double angular_resolution = 0.1*TMath::Pi()/180.;
//	    double angular_resolution = 0;

	    double mom = cur->P();

	    double theta = cur->Theta();
	    double phi   = cur->Phi();

	    double mom_measured   = PUtils::sampleGaus(mom, mom*momentum_resolution);
	    double theta_measured = PUtils::sampleGaus(theta, angular_resolution);
	    double phi_measured   = PUtils::sampleGaus(phi, angular_resolution);

	    cur->SetRho(mom_measured);
	    cur->SetTheta(theta_measured);
	    cur->SetPhi(phi_measured);

 	    cur->ResetE();
#endif
	    

	    if (cur->Theta() < ((18./180)*TMath::Pi())){
		*hadacc=0.;
		//cur->Print();
	    }
	    if (cur->Theta() > ((88./180)*TMath::Pi())){
		*hadacc=0.;
		
	    }
	    if (cur->P() < 0.1)  {
		*hadacc=0.;
		
	    }
	}
    }

    *opang = 1.;

    //the opang:
    for (int i=0; i<*num; i++) {
	PParticle *ep = stack[i];
	if (ep->Is("e+")) {
	    for (int i=0; i<*num; i++) {
		PParticle *em = stack[i];
		if (em->Is("e-")) {
		    Double_t oa = ep->Vect().Angle(em->Vect());
		    if (oa < ((4./180)*TMath::Pi())){
			*opang = 0.;
		    }
		}
	    }
	}
    }

    return kTRUE;
};